scholarly journals Label-free quantitation of glycated hemoglobin in single red blood cells by transient absorption microscopy and phasor analysis

2019 ◽  
Vol 5 (5) ◽  
pp. eaav0561 ◽  
Author(s):  
Pu-Ting Dong ◽  
Haonan Lin ◽  
Kai-Chih Huang ◽  
Ji-Xin Cheng
Keyword(s):  
Transient Absorption ◽  
Glycated Hemoglobin ◽  
Blood Glucose Concentration ◽  
Label Free ◽  
Absorption Imaging ◽  
Fraction Distribution ◽  
Boronate Affinity Chromatography ◽  
Volume Blood ◽  
Phasor Analysis

As a stable and accurate biomarker, glycated hemoglobin (HbA1c) is clinically used to diagnose diabetes with a threshold of 6.5% among total hemoglobin (Hb). Current methods such as boronate affinity chromatography involve complex processing of large-volume blood samples. Moreover, these methods cannot measure HbA1c fraction at single–red blood cell (RBC) level, thus unable to separate the contribution from other factors such as RBC lifetime. Here, we demonstrate a spectroscopic transient absorption imaging approach that is able to differentiate HbA1c from Hb on the basis of their distinct excited-state dynamics. HbA1c fraction inside a single RBC is derived quantitatively through phasor analysis. HbA1c fraction distribution of diabetic blood is apparently different from that of healthy blood. A mathematical model is developed to derive the long-term blood glucose concentration. Our technology provides a unique way to study heme modification and to derive clinically important information void of bloodstream glucose fluctuation.

scholarly journals Direct and Label-Free Determination of Human Glycated Hemoglobin Levels Using Bacteriorhodopsin as the Biosensor Transducer

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7274
Author(s):  
Ying-Chin Lin ◽  
Ching-Yu Lin ◽  
Hsiu-Mei Chen ◽  
Li-Pin Kuo ◽  
Cheng-En Hsieh ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Glycated Hemoglobin ◽  
Incident Light ◽  
Protein A ◽  
Cross Reactivity ◽  
Single Step ◽  
Clinical Samples ◽  
Label Free ◽  
Hba1c Levels

Glycated hemoglobin (HbA1c) levels are an important index for the diagnosis and long-term control of diabetes. This study is the first to use a direct and label-free photoelectric biosensor to determine HbA1c using bacteriorhodopsin-embedded purple membranes (PM) as a transducer. A biotinylated PM (b-PM) coated electrode that is layered with protein A-oriented antibodies against hemoglobin (Hb) readily captures non-glycated Hb (HbA0) and generates less photocurrent. The spectra of bacteriorhodopsin and Hb overlap so the photocurrent is reduced because of the partial absorption of the incident light by the captured Hb molecules. Two HbA0 and HbA1c aptasensors that are prepared by conjugating specific aptamers on b-PM coated electrodes single-step detect HbA0 and HbA1c in 15 min, without cross reactivity, with detection limits of ≤0.1 μg/mL and a dynamic range of 0.1–100 μg/mL. Both aptasensors exhibit high selectivity and long-term stability. For the clinical samples, HbA0 concentrations and HbA1c levels that are measured with aptasensors correlate well with total Hb concentrations and the HbA1c levels that are determined using standard methods (correlation gradient = 0.915 ± 0.004 and 0.981 ± 0.001, respectively). The use of these aptasensors for diabetes care is demonstrated.

scholarly journals Nanoparticle Determination in Water by LED-Excited Surface Plasmon Resonance Imaging

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 175
Author(s):  
Lukas Wunderlich ◽  
Peter Hausler ◽  
Susanne Märkl ◽  
Rudolf Bierl ◽  
Thomas Hirsch
Keyword(s):  
Light Source ◽  
Self Assembled Monolayers ◽  
Receptor Interaction ◽  
Complex Nature ◽  
Label Free ◽  
Quality Of Water ◽  
Spr Imaging ◽  
Online Sensor ◽  
Assembled Monolayers

The increasing popularity of nanoparticles in many applications has led to the fact that these persistent materials pollute our environment and threaten our health. An online sensor system for monitoring the presence of nanoparticles in fresh water would be highly desired. We propose a label-free sensor based on SPR imaging. The sensitivity was enhanced by a factor of about 100 by improving the detector by using a high-resolution camera. This revealed that the light source also needed to be improved by using LED excitation instead of a laser light source. As a receptor, different self-assembled monolayers have been screened. It can be seen that the nanoparticle receptor interaction is of a complex nature. The best system when taking sensitivity as well as reversibility into account is given by a dodecanethiol monolayer on the gold sensor surface. Lanthanide-doped nanoparticles, 29 nm in diameter and with a similar refractive index to the most common silica nanoparticles were detected in water down to 1.5 µg mL−1. The sensor can be fully regenerated within one hour without the need for any washing buffer. This sensing concept is expected to be easily adapted for the detection of nanoparticles of different size, shape, and composition, and upon miniaturization, suitable for long-term applications to monitor the quality of water.

scholarly journals Label-Free Study of the Global Cell Behavior during Exposure to Environmental Radiofrequency Fields in the Presence or Absence of Pro-Apoptotic or Pro-Autophagic Treatments

2022 ◽  
Vol 23 (2) ◽  
pp. 658
Author(s):  
Alexandre Joushomme ◽  
André Garenne ◽  
Mélody Dufossée ◽  
Rémy Renom ◽  
Hermanus Johannes Ruigrok ◽  
...  
Keyword(s):  
Mobile Communications ◽  
Cellular Response ◽  
Continuous Wave ◽  
Digital Holographic Microscopy ◽  
Label Free ◽  
Environmental Signals ◽  
Chemical Treatments ◽  
Rf Exposure ◽  
Universal Mobile Telecommunications System

It remains controversial whether exposure to environmental radiofrequency signals (RF) impacts cell status or response to cellular stress such as apoptosis or autophagy. We used two label-free techniques, cellular impedancemetry and Digital Holographic Microscopy (DHM), to assess the overall cellular response during RF exposure alone, or during co-exposure to RF and chemical treatments known to induce either apoptosis or autophagy. Two human cell lines (SH-SY5Y and HCT116) and two cultures of primary rat cortex cells (astrocytes and co-culture of neurons and glial cells) were exposed to RF using an 1800 MHz carrier wave modulated with various environmental signals (GSM: Global System for Mobile Communications, 2G signal), UMTS (Universal Mobile Telecommunications System, 3G signal), LTE (Long-Term Evolution, 4G signal, and Wi-Fi) or unmodulated RF (continuous wave, CW). The specific absorption rates (S.A.R.) used were 1.5 and 6 W/kg during DHM experiments and ranged from 5 to 24 W/kg during the recording of cellular impedance. Cells were continuously exposed for three to five consecutive days while the temporal phenotypic signature of cells behavior was recorded at constant temperature. Statistical analysis of the results does not indicate that RF-EMF exposure impacted the global behavior of healthy, apoptotic, or autophagic cells, even at S.A.R. levels higher than the guidelines, provided that the temperature was kept constant.

scholarly journals The phosphoproteome of rice leaves responds to water and nitrogen supply

2021 ◽  
Author(s):  
Sara Hamzelou ◽  
Vanessa J. Melino ◽  
Darren C. Plett ◽  
Karthik Shantharam Kamath ◽  
Arkadiusz Nawrocki ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
Water Channel ◽  
Nitrogen Supply ◽  
Nitrogen Fertilizers ◽  
Label Free ◽  
Limited Information ◽  
Irrigated Rice ◽  
Post Translational Modifications ◽  
Growth Adaptation

The scarcity of freshwater is an increasing concern in flood-irrigated rice, whilst excessive use of nitrogen fertilizers is both costly and contributes to environmental pollution. To co-ordinate growth adaptation under prolonged exposure to limited water or excess nitrogen supply, plants have processes for signalling and regulation of metabolic processes. There is limited information on the involvement of one of the most important post-translational modifications (PTMs), protein phosphorylation, on plant adaptation to long-term changes in resource supply. Oryza sativa cv. Nipponbare was grown under two regimes of nitrogen from the time of germination to final harvest. Twenty-five days after germination, water was withheld from half the pots in each nitrogen treatment and low water supply continued for an additional 26 days, while the remaining pots were well watered. Leaves from all four groups of plants were harvested after 51 days in order to test whether phosphorylation of leaf proteins responded to prior abiotic events. The dominant impact of these resources is exerted in leaves, where PTMs have been predicted to occur. Proteins were extracted and phosphopeptides were analysed by nanoLC-MS/MS analysis, coupled with label-free quantitation. Water and nitrogen regimes triggered extensive changes in phosphorylation of proteins involved in membrane transport, such as the aquaporin OsPIP2-6, a water channel protein. Our study reveals phosphorylation of several peptides belonging to proteins involved in RNA-processing and carbohydrate metabolism, suggesting that phosphorylation events regulate the signalling cascades that are required to optimize plant response to resource supply.

Glycated hemoglobin in fractionated erythrocytes.

1989 ◽  
Vol 35 (6) ◽  
pp. 958-962 ◽  
Author(s):  
K Nakashima ◽  
O Nishizaki ◽  
Y Andoh ◽  
H Takei ◽  
A Itai ◽  
...  
Keyword(s):  
Glycated Hemoglobin ◽  
Normal Subjects ◽  
Middle Aged ◽  
Glycemic Status ◽  
Hb A1c ◽  
Cell Age ◽  
Initial Stage ◽  
Treatment Of Diabetes ◽  
Term Monitoring

Abstract Erythrocytes were fractionated, by centrifugation, on the basis of cell density, which is proportional to cell age. Glycated hemoglobin (Hb A1c) in the fractionated cells was measured and compared with the Hb A1c in whole blood and with the fructosamine concentrations in plasma of normal and diabetic subjects. In normal subjects, Hb A1c increased according to the age of the erythrocytes, but hyperbolically rather than linearly, indicating the slow conversion of Hb A to Hb A1c with saturability. The greatest correlation of Hb A1c with plasma fructosamine was in younger middle-aged cells. A subgroup of subjects with impaired glucose tolerance had high Hb A1c in older cells. Hb A1c of the young cells reflects recent glycemic status, for monitoring the initial stage of the treatment of diabetics, whereas Hb A1c of the older middle-aged cells more specifically reflects the longer term glycemic status, for screening and for the long-term monitoring index for treatment of diabetes.

Association of fasting glucose and glycated hemoglobin with the long-term risk of incident metabolic syndrome: Korean Genome and Epidemiology Study (KoGES)

2019 ◽  
Vol 56 (5) ◽  
pp. 551-559 ◽  
Author(s):  
Ju Young Jung ◽  
Jae-Hong Ryoo ◽  
Pil-Wook Chung ◽  
Chang-Mo Oh ◽  
Joong-Myung Choi ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Glycated Hemoglobin ◽  
Fasting Glucose ◽  
Epidemiology Study

Long-Term Safety and Efficacy of Programmable Implantable Insulin Delivery Systems

1993 ◽  
Vol 16 (12) ◽  
pp. 847-854 ◽  
Author(s):  
C.L. Olsen ◽  
G. Liu ◽  
M. Iravani ◽  
S. Nguyen ◽  
K. Khourdadjian ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Standard Deviation ◽  
Insulin Infusion ◽  
Glycated Hemoglobin ◽  
Severe Hypoglycemia ◽  
Insulin Delivery ◽  
Delivery Systems ◽  
Subcutaneous Insulin ◽  
Safety And Efficacy

Objectives Since only short-term studies of continuous intraperitoneal insulin infusion (CIPII) therapy using implantable programmable insulin delivery systems have been performed to show this method of diabetes therapy to be safe and efficacious, we have performed long-term studies to assess its safety and efficacy. Research design and methods For 78 patient-years of follow-up, we have longitudinally studied the incidence of diabetic ketoacidosis and severe hypoglycemia in 25 type 1 diabetic patients treated with CIPII. We also compared, cross-sectionally, the long-term safety and efficacy of CIPII to intensive subcutaneous insulin therapy using intermittent injections or continuous subcutaneous insulin infusion. Finally, we examined the relationship between glycated hemoglobin levels and the standard deviation of daily blood glucose excursion. Results Cross-sectional analysis revealed similar degrees of metabolic control accompanied by significantly decreased rates of both ketoacidosis (0.013 events/patient/year) and severe hypoglycemia (0.05 events/patient/year) during CIPII compared to intermittent injections and continuous subcutaneous insulin infusion therapy. A four-fold decrease in the rate of severe hypoglycemia was observed during longitudinal comparison of pre- and post-implantation complication rates. A relationship was also shown between decreased levels of mean glycated hemoglobin and the standard deviation of blood glucose excursions during CIPII therapy. Conclusions Our data demonstrate that long-term therapy with CIPII is as effective as other methods in achieving near-normal levels of glycated hemoglobin, which in CIPII is associated with a decreased standard deviation of blood glucose excursions. Further, CIPII using implantable programmable insulin delivery systems is the safest method described for intensive insulin therapy in home blood glucose monitoring type 1 diabetic patients.

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